With the increase in heat dissipation from microelectronic devices and the reduction in overall form factors, thermal management becomes a more and more important element of electronic product design. Both the performance reliability and life expectancy of electronic equipment are inversely related to the component temperature of the equipment.
Heat sinks function by efficiently dissipating thermal energy (i.e., “heat”) generated from an object (e.g., electronic module or microelectronic component) into a cooler ambient, e.g., the air; and at least transfer thermal energy from an object at a high temperature to a second object at a lower temperature with a much greater heat capacity.
In a common design of a heat sink, a metal plate having a flat surface (e.g., a copper or aluminum base) is provided with an array of cooling structures, e.g., combs or fin-like protrusions to increase the heat sink's surface area contacting the air and thus increase the heat dissipation rate. A high thermal conductivity of the metal base combined with its large surface area provided by the protrusions result in the rapid transfer of thermal energy to the surrounding, cooler air.
Liquid cold plates, on the other hand, provide an alternative advantage over some air cooled solutions in high watt density applications and may include tubed cold plates, flat tube cold plates, performance-fin cold plates and liquid-cooled chassis designs.
FIG. 1 shows a cross-sectional view of a current design of a portion of a thin-plate-based cold plate or heat sink 10. In a current embodiment, the heat sink includes parallel formed planar members including a top thin-walled plate member 12, a bottom thin-walled plate member 15 and sidewall structures (not shown) that form a space or chamber 19 for air or fluid flow therein. Inserted within the chamber 19 affixed between parallel top thin-wall and bottom thin-wall plates are a plurality of traverse oriented fins 25 that are oriented to provide one or more communicating air or liquid medium flow paths therein.
In order to withstand a “burst pressure” defined as the point at which the cold plate or heat sink will fail as a result of pressure (e.g., a point determined by providing a liquid flow with force into the communicating flow path inside the hear sink and observing what portions would be broken by the high pressures), the top thin-walled plate 12 and bottom thin-walled plate 15 are currently held together using separate plural support posts 20, two of which are shown in FIG. 1.
In such embodiments, each opposing end 30 of a respective post 20 is soldered or brazed onto the respective top and bottom thin plates as shown in FIG. 1. There is a great cost in implementing these posts, and their manufacture and widespread use in cold plate and heat sink devices are becoming prohibitive.